package com.tdrc.common.core.shiro;

import com.alibaba.druid.util.StringUtils;
import com.tdrc.common.beans.ResultCode;
import com.tdrc.common.util.HttpServletResponseUtil;
import com.tdrc.common.util.JsonResult;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author dpf
 * @version 1.0
 * @date 2020-5-22 15:19
 * @instruction ...
 */
public class JwtFilter extends BasicHttpAuthenticationFilter {
    private Logger log = LoggerFactory.getLogger(JwtFilter.class);
    /**
     * 判断用户是否想要登入。
     * 检测header里面是否包含Authorization字段即可
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse)response;
        httpServletRequest.getHeaderNames();
        String access_token = httpServletRequest.getHeader("access-token");
        //这只判断access_token是否为空
        if(!StringUtils.isEmpty(access_token)){
            access_token = access_token.substring(7);
            // 判断token是否过期
            log.info("判断用户是否想要登录：{}",access_token);
            return true;
        }else{
            HttpServletResponseUtil.printJson(httpServletResponse,new JsonResult(ResultCode.PERMISSION_UNAUTHORISE));
            return false;

        }
    }

    /**
     *执行登录
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response)  {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String access_token = httpServletRequest.getHeader("access-token").substring(7);
        log.info("判断用户是否想要登录x：{}",access_token);
        JwtToken token = new JwtToken(access_token);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(token);
        return true;
    }

    /**
     * 这里我们详细说明下为什么最终返回的都是true，即允许访问
     * 例如我们提供一个地址 GET /article
     * 登入用户和游客看到的内容是不同的
     * 如果在这里返回了false，请求会被直接拦截，用户看不到任何东西
     * 所以我们在这里返回true，Controller中可以通过 subject.isAuthenticated() 来判断用户是否登入
     * 如果有些资源只有登入用户才能访问，我们只需要在方法上面加上 @RequiresAuthentication 注解即可
     * 但是这样做有一个缺点，就是不能够对GET,POST等请求进行分别过滤鉴权(因为我们重写了官方的方法)，但实际上对应用影响不大
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue)    {
        if (isLoginAttempt(request, response)) {
                executeLogin(request, response);
                return true;
        }else{
            return false;
        }

    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }
}
